2. Soils2.1. The role of soil in the ecosystem1) Production of food and other biomass.2) Environmental interaction such as storage, filtering and processing i.e. wetlands.3) Biological habitat for soil organisms.4) Source of raw materials.5) Platforms for human-built structures such as buildings, highways, etc.6) Nutrient and organic waste recycling system i.e. decomposition.7) Nitrogen fixation which is the process by which atmospheric nitrogen is absorbed into organic compounds by soil microorganisms.8) Medium for plant growth by providing nutrients to plants.DefinitionsSoil erosion: Is it the wearing away of the topsoil – the top layer of nutrient-rich soil, by the natural physical forces of water and wind or by forces associated with agricultural activities. Soil erosion reduces the productivity of cultivated land and contributes to the pollution of nearby rivers, wetlands and lakes. Soil is a non-renewable resource. Desertification: Without soil and plants, the land becomes desert and unable to support life. Stream: something that drains or flows from land into watercourses. Loss of protective vegetation due to deforestation, overgrazing, plowing and fires leaves the soil vulnerable to wind and water. The amount of soil that wind and water can carry away is influenced by two factors. :o Speed ​​- The faster the wind or water moves, the more soil can erode. o Plant cover – Plants that protect the soil and, in their absence, wind and water can cause much more damage.2.2. Causes of Soil Erosion1) Overgrazing, i.e. excessive numbers of cattle and overgrazing, i.e. when cattle eat the grass down to the root level. So less chance of it growing back.2) Inappropriate farming techniques...... middle of paper ...... larger animals which are then consumed by animals at the top of the food chain. The impact of climate changes on a particular species can propagate through a food web and affect a wide range of other organisms.o Initiation effects: Coral bleaching: When coral reefs are stressed, they expel micro- organisms that live in their tissues and are essential to their health. As ocean temperatures warm and ocean acidity increases, coral bleaching and death become common and are unable to recover. o Pathogens, parasites and diseases: Climate change and changes in ecological conditions could favor the spread of pathogens and parasites. and disease, with potentially serious effects on human health, agriculture and fisheries.o Extinction risks: Climate change, along with habitat destruction and pollution, may contribute to extinction species..